AMARILLO, TEXAS -- A 75-year-old Amarillo man died Tuesday afternoon after police said he backed out of his driveway and struck a tree.

Police were called to the 3400 block of Amherst Drive just before 1:00 p.m. Tuesday on a traffic accident.

According to authorities, the driver of a maroon 2000 Buick, 75-year-old Macky Douglas Oldfield, backed out of his home's driveway, accelerated sharply in reverse and crossed the street. Police said the vehicle then continued over the curb into a yard before striking a tree.

Upon arrival, police said Oldfield was unresponsive. He was transported to the hospital where he was later pronounced dead.

Police said he may have suffered from a medical emergency that caused him to accelerate into the tree.

An autopsy has been ordered and the incident remains under investigation, police said.